This invention relates to an apparatus for control of a strobe lamp. Strobe lamps of the type sought to be controlled typically comprise a chamber in which there are two power electrodes and a gas which is capable of ionization. Typically the strobe lamp has a large potential placed across the two electrodes. When the firing of the lamp is desired, a firing pulse will be applied to a third electrode, the firing or trigger electrode. This firing pulse will ionize the gas sufficiently to allow current to flow between the two power electrodes with the result that the strobe lamp is flashed. The power supply for this type of lamp is generally a bank of capacitors in parallel with the lamp.
One problem that is prevalent in controlling this sort of lamp is that, after the lamp is flashed, the gas in the lamp will remain ionized in an effect called "after-glow". A strobe lamp experiencing after-glow cannot be flashed. If the capacitor bank is recharged while the strobe lamp is experiencing after-glow, the after-glow effect will be perpetuated and therefore further firing of the strobe lamp will be prevented.
One approach to solving the after-glow problem has been to utilize a sufficiently weak voltage source to recharge the capacitor bank such that the charging rate of the capacitor bank is less than the discharge rate of the strobe lamp experiencing after-glow. The capacitor bank will then discharge through the strobe lamp until the voltage across the lamp drops below the minimum conduction voltage of the lamp. When this occurs, the after-glow will terminate and the capacitor bank may then be recharged.
Where a high intensity strobe lamp requiring a great deal of power is to fired at a fairly rapid rate, as for example an aircraft anti-collision light, a powerful voltage supply is needed to recharge rapidly the capacitor bank. Such a voltage supply will charge the capacitors and maintain the strobe lamp in its after-glow condition, thus preventing the lamp from being fired. The varying ambient temperatures to which aircraft strobe lamps are subjected can accentuate this problem. For example, in a cold environment, the after-glow effect will more readily occur and will persist for a greater length of time.
An additional problem encountered with aircraft strobe lamp arrangements is that quite often more than one set of strobe lamps is desired to be flashed. Typically one set of lamps will be used during the day and a second set of lamps, having different energy requirements, will be used at night. In the past a separate capacitor bank has been used for each set of strobe lamps to compensate for the varying energy requirements. Such an arrangement is wasteful of space and weight and is thus disadvantageous in an aircraft application.